Problem: A rectangular prism with length $\ell$, width $w$, and height $h$ has a volume of $\ell w h$. What is the volume of a prism which has a base of $5\text{ m}$ by $3\text{ m}$, and a height of $4\text{ m}$ ?
Solution: A prism which has a base of $5\text{ m}$ by $3\text{ m}$ and a height of $4\text{ m}$ tells us that $\ell={5}$, $w={3}$, and $h={4}$. Let's substitute $\ell={5}$, $w={3}$, and $h={4}$ into the expression and evaluate: $\begin{aligned} &\phantom{=}\ell wh\\\\ &= {5}({3})(4)\\\\ &= 5(12)\\\\ &= {60} \end{aligned}$ The prism with a base of $5\text{ m}$ by $3\text{ m}$ and a height of $4\text{ m}$ has a volume of ${60}\text{ m}^3$.